Preliminary research from Smith-Kettlewell Eye Research Institute in San Francisco suggests certain vision problems in older adults is associated with a 50% higher risk of hearing loss.  Here is a summary of the research by Marilyn Schneck and colleagues:


446 adults with a mean age of 79.9 years had their hearing screened and underwent an extensive series of visual tests.  The visual tests categorized the subjects according to their acuity in high and low contrast situations where lighting was varied.  Results showed that vision ability in low contrast situations decreased with age (white bars, Figure 1).

Hearing loss was only measured by a hearing screening, not in-depth testing of the type done on the vision of the subjects.  Nevertheless, the results were consistent with what we know about the general population:  hearing loss increases with age (black bars in Figure 1), as did  increased vision impairment, the white bars in Figure 1.


Figure 1. Rates of hearing impairment (black bars), vision impairment (white bars) and dual sensory impairment (gray bars) across age groups


Of most interest is that subjects who had decreased visual performance were more likely to also have hearing difficulty and that effect was also age dependent (gray bars, Figure 1).

Let’s get back to that “low contrast” part of the study.  If you are like us, low contrast sensitivity doesn’t mean much, so we looked into it further and found this helpful illustration:


How it looks to someone with low contrast sensitivity

how it looks to someone with normal contrast sensitivity



People who have low visual contrast sensitivity see a scene with … not much contrast. It gets all hazy and it is literally hard to see the trees for the forest or whatever background surrounds the trees. Those with normal vision see everything distinctly and  in technicolor, as in the right picture.

When you think about it for a minute, this is an excellent analogy to what happens to people who lose some of their hearing with age. Those people don’t complain that they are deaf — they can still hear.  Instead, they complain that they can’t distinguish speech in noise — that it is all blending together, the clarity is gone, it’s getting hazy.  Though they don’t use the word “contrast,” that is what they are really saying — there is too little contrast between the noise and speech to allow them to easily “hear” in the haze.

This is exciting research although it just scratches the surface.  We are hopeful that the scientists at Smith Kettlewell will pursue this interesting line of research. We’re also hopeful that they will be joined by audiologists and psychoacousticians who will add important hearing measures to the research protocol.  Just as subjects in this study were tested for high and low contrast visual stimulus sets, it would be very useful to know how those same subjects performed on speech-in-noise tests.  If the performance deficits are similar between vision and hearing modalities, the next steps in the research might find similar physiological substrates to explain the findings.

None of this will happen overnight, of course, but we’ll keep checking in and let you know if anything comes up.



Schneck, M.E., Lott, L.A., Haegerstrom-Portnoy, G., Braby, J.A., Association between hearing and vision impairments in older adults, Ophthalmic and Physiological Optics, Volume 32, Issue 1, pages 45–52, January 2012


*This article was originally published at the Audiology condition on July 12, 2016. Images courtesy of and Contrast Sensitivity Testing

This post, originally published in April of 2017, is “most read and shared,” though perhaps not “best.”

Despite United’s persistent efforts to discourage air travel for people who are teenagers, wear leggings, or have assigned seats, it’s likely that many readers have a trip planned by air in the near future. Those who wear hearing aids may wonder what’s in store for them, their hearing aids, and their batteries when checking luggage, clearing security, and getting airborne.  

Don’t worry — even United won’t remove you for wearing hearing aids or carrying extra batteries, even if you’re a teenager. But there are a few rules and regs to keep in mind.

Homeland Security, TSA, different airports, different airlines, differently-equipped planes, domestic flights, international travel — all have requirements for electronics devices and power supplies. It’s hard to keep up with the requirements, which vary for according to agency, airline, country, equipment, and year.  And, of course, ear level technology keeps changing as well.  

Here are a few nuggets to help with your travel plans this year.   


Packing Your Bags

Table 1.  Some of the TSA guidelines for batteries in checked and carry-on luggage.

If you pack your hearing aids or a back-up set in carry-on luggage, TSA may subject them to additional screening, at their discretion.

Odds are that you’ll probably wear your hearing aids and carry your Smartphone onto the plane. So, packing concerns are mainly about extra batteries. As Table 1 shows, you’re good to go so long as the spare batteries are packed in your carry-on bag. If they are for personal use, the number you carry on are not restricted.

If your hearing aids operate on replaceable zinc-air batteries (e.g., 10A, 312A, 13A, 675A), you can put those in your checked baggage as well. Not so if you use the Lithium ion (Li-ion) rechargeable batteries, which are fine in your hearing aids and carry-on (so long as they are not loose), but can’t be packed as spares in checked luggage unless they’re in a set of hearing aids.

Those are the general guidelines.  But also note the fine print in the second from top line of Table 1:

“TSA security, individual airline, and international rules may, at times, be more restrictive.”  


More on Li-ion Batteries


travel website offers the following safety recommendations for using and traveling with Li-ion batteries. 

  1. Buy your batteries from reputable sources and look for the mark of independent testing such as the Underwriters Laboratories (UL) or International Electrotechnical Commission (IEC). Counterfeit batteries are more likely to cause a fire in your equipment.
  2.  If you are carrying spare batteries, keep them in your carry-on luggage.
  3. Prevent potential short-circuiting by keeping the batteries in their original retail packaging or by placing tape across the contacts to isolate the terminals.
  4. Keep each battery away from other batteries and metal objects such as coins, keys, and jewelry.
  5. Pack your batteries carefully to avoid crushing, puncturing, or any high degree of pressure on the battery, which can result in an internal short-circuit and risk overheating and fire.
  6. If you pack a device containing batteries, secure the device against accidental activation by locking it, placing it in a protective case, etc.”


Getting Through Security Screening


Fig Download, fill out, present at airport security

The two chief take-homes are:

  • You don’t need to remove hearing aids or the exterior component of a cochlear implant at security checkpoints. 
  • Wear your hearing devices while going through the screenings. Hearing aids are not harmed by “X-rays, walk-through metal detectors, full-body scanners, or hand-help detection devices.”

According to the “Deaf or Hard of Hearing” section on TSA’s website, you should:

  • “Inform the TSA officer if you are deaf or hard of hearing and require assistance with the screening process. You may provide a TSA notification card or other medical documentation to inform the TSA officer.” (Fig 1)
  • “you are not required to remove any hearing aids or cochlear implants. Additional screening, including a pat-down or inspection of a device, may be required if it alarms a walk-through metal detector or appears as an anomaly when screened by advanced imaging technology.”


Once You’re Airborne


The FAA exempts hearing aids from the rules governing other portable electronic devices. Besides their obvious health-related functionality, the exemption is because the signals from  hearing aids and other health devices such as pacemakers don’t interfere with aircraft controls and communication.

New Bluetooth hearing aids that communicate via Smartphone apps are not quite the same thing.  The FAA updates its rules periodically to keep pace with technological advances of this kind.  It loosened requirementsfor personal electronics in October 2013. The present stance, which will surely change as aircraft change, states:

Devices must be used in airplane mode or with the cellular connection disabled. You may use the WiFi connection on your device if the plane has an installed WiFi system and the airline allows its use.  You can also continue to use short-range Bluetooth accessories, like wireless keyboards.

It is with this in mind that hearing aid instruction manuals for Bluetooth-equipped hearing aids have added another page to their instructions.  For instance, the Oticon OPN instruction manual has this to say on page 51:   “Use on Aircraft • Your hearing aid contains Bluetooth. On board an aircraft, flight mode must be activated, unless Bluetooth is permitted by the flight personnel.”

This brings up a new twist for Bluetooth users on planes.  Streaming content from your iPad to your hearing aids is a good way to pass the time on a long flight, but is also a good way to use up power on all devices.  While it’s easy enough to pop spare batteries into your hearing aids, it’s not as easy to charge the iPad. A dead iPad is usually just a nuisance, but it’s more than that when it comes to TSA.  According to a Forbes article on the topic:

“Travelers heading back to the United States from an overseas trip through certain airports are going to need to make certain that their phone, tablet, or laptop is still powered up enough to turn on for the TSA inspectors. This can be a hassle to ensure, especially after a long flights or heavy usage.”

When in doubt, or when there’s a tight connection between flights, turn off Wifi and Bluetooth.


 In Conclusion


Have a good flight. Pack carefully. Hand them your TSA card. Don’t wear leggings. Don’t give up your seat without a fight. If you must fight, be sure to scream loudly, get it on video, and hold on to your hearing aids. 




FAA. Press Release – FAA to Allow Airlines to Expand Use of Personal Electronics. October 31, 2013.

Tobias MW. How To Make Sure Your Electronic Devices Get Through Airport Security. Forbes, 8/08/2014.


images courtesy of